1. Field of the Invention
This invention relates to an apparatus for flattening and removing plastic tubular film made by a blowmolding process by means of a stationary film-blowing head. In such apparatus flattening plates and squeeze rollers are reversibly pivotally movable about the axis of the tubular film coming from the blowing head, and are succeeded by a stationary winding or afterprocessing means. The apparatus further comprises a radially outer turning rod, or roller which is parallel to and reversibly swingable with the squeeze rollers and a radially inner turning rod, around which the tubular film is trained between the squeeze rollers and the winding or afterprocessing apparatus. The reversible deflecting roller, the turning rod and any stationary deflecting roller extend in planes which are parallel to the plane in which the squeeze rollers can swing and the distance from the reversible deflecting roller to the swing axis is larger in any possible angular position than the distance from the film-contacting portion of the turning rod to the swing axis. The angle of the pivotal or swinging movement of the turning rod is one-half the angle of pivotal movement of the deflecting roller.
2. Description of the Prior Art
One known apparatus of the kind referred to is disclosed, for example, in U.S. Pat. No. 3,768,949.
In another apparatus of the kind referred to which is disclosed in German Patent Specification 21 56 079, the turning rod is movably mounted in holders provided on a reversibly rotatable vertical shaft, which at its bottom end carries a frame, in which the squeeze rollers and the reversible deflecting roller are rotatably mounted and the flattening plates are secured. Because the turning rod must be disposed close to the vertical shaft and the distance from the turning rod to the shaft can be altered only within close limits, the diameter of the turning rod can also be altered only within close limits so that the diameter of the turning rod cannot be increased indiscriminately although this may be desirable. For this reason the known apparatus involves a limitation of the diameter of the turning rod and the turning rod is disposed close to the vertical shaft which carries that rod so that it is difficult to train the tubular film around that turning rod as the apparatus is set up.